Data Network Design and Management

• A data network is a collection of devices and circuits for transferring data from one computer to another, including devices like printers.
• Data networks enable users at different locations to share resources of a computer located elsewhere, such as with ATMs.

Goals of Network Design

• The primary goal is to meet the organization's communication needs.
• Network design aims to increase productivity and reduce budget.

Considerations for Network Design

• Network design requires a comprehensive plan that considers:
• Suitability
• Reliability
• Scalability
• Durability

Role of a Network Engineer/Administrator

• Network engineers install, maintain, troubleshoot, optimize, and expand networks.
• As networks grow, the potential problems also increase.
• Network Management helps network engineers deal with the complexity of data networks.
• Network Management principles are fundamental to network design.

The Network Management Process

• Network Management controls complex data networks to maximize their efficiency and productivity.

ISO Framework for Network Management

• A framework comprising:
• Configuration management
• Security management
• Performance management
• Accounting management
• Fault management

Configuration Management

• Configuration management gathers data about the current network environment
• Configuration management uses gathered data to modify network device configurations.
• Configuration management also stores data, maintains an up-to-date inventory of all network components, and generates reports.

Data Collection, Modification, and Storing

• Two methods of data collection:
• Manual collection: Tedious and error-prone
• Auto-discovery/Auto-mapping: uses ICMP (ping, traceroute) and Network Management Protocols
• Configuration management information must be updated after being obtained.
• Network devices usually contain many pieces of modifiable parameters, like routers, servers etc.

Storing Information Methods

• Unstructured (e.g., ASCII files):
• Advantages: Easily read, accessed remotely, and administered.
• Disadvantages: Inefficient storage, slow search, and inability to show complex relationships.
• Structured (e.g., DBMS):
• Advantages: Efficient data storage, ability to relate data, and versioning.
• Disadvantages: Requires query language knowledge (e.g., SQL) and administrative overhead.

Configuration Management Benefits

• Automatically gathers and updates data on network devices.
• Allows for remote configuration of devices.
• Provides a central storage location for configuration data.
• Facilitates network inventory reports.

Security Management

• Involves protecting sensitive information on devices by controlling access points.
• Security management involves:
• Identifying sensitive data.
• Finding vulnerabilities.
• Securing access points.
• Maintaining secure access points.

Security Management Benefits

• Increases confidence in using the network.
• Addressing a lack of security may force drastic measures, such as completely eliminating network access of sensitive information.
• Proper maintenance offers practical alternatives.
• Examples of security breaches include the 1988 internet worm and more recent ICMP and TCP based DoS attacks.

Performance Management

• Performance management ensures networks remain accessible and congestion-free.
• This involves:
• Monitoring network devices and their links to determine utilization and error rates.
• Helping the network provide consistent quality of service (QoS) by ensuring devices and links are not overloaded, impacting performance.

Performance Management Steps

• Performance management follows these steps:

1. Data collection on current utilization of devices and links
2. Data analysis. including statistical analysis and workload modeling
3. Setting utilization thresholds
4. Using simulation to optimize network performance

Performance Terms

• Availability
• Bandwidth/Throughput
• Propagation
• Congestion
• Latency
• Threshold
• Utilization

Performance Management Benefits

• Reduces the chance of network congestion and inaccessibility, providing consistent service.
• Analyzing the network's utilization workload helps schedule large data transfers during non-peak hours.
• Aids content creators, hosting companies, network operators, and networking researchers in examining network trends.

Accounting Management

• Its the process of gathering network statistics, which help network engineers make decisions about the allocation of network resources.
• Involves gathering data on the utilization of network resources using metrics like that defined in RFC 1272.
• This includes application layer per-transaction metrics and network layer packet counts.
• Also includes setting usage quotas and billing users for network use.

Accounting Management Benefits

• Allows effective measurement and reporting of accounting information.
• Increases the engineer's understanding of user utilization, enabling informed decisions about resource allocation and fairness.

Fault Management

• Locates problems or faults on the data network.
• Includes detecting symptoms, isolating their cause, and correcting the problem if possible.
• The process involves detecting symptoms, isolating causes, finding correlations between symptoms and potential problems, and correcting the issue, if possible.

Gathering Information for Fault Management

• Interrupt driven: Responds to critical events but may not facilitate effective fault management.
• Polling: Finds faults in a timely manner, using higher bandwidth consumption and it is implementable using ICMP messages (ping)

Fault Management Benefits

• Enhances network reliability by aiding in rapid fault detection, isolation, and recovery.
• Maintains complete and continuous connectivity between users and the network.

Network Management Systems (NMS)

• Comprises an underlying architecture (platform) that provides generic/basic network management functionality.
• Also a set of applications built on top of that platform.

Example NMSS

• Commercial implementations: HP Openview, SunConnect SunNet Manager, and IBM Netview
• Freeware implementations: Net-SNMP and OpenNMS

NMS Platform Functionality.

• Contains:
• User interface
• Network map
• Database Management System (DBMS) / Management Information Base (MIB)
• Query language
• Customizable menu system
• Event log

Network Management Architecture

• An NMS platform can use three architectures:
• Centralized
• Distributed
• Hierarchical